There have been known many species of π-conjugated conducting polymer having sulfonic acid groups. One of them is polythiophene capable of self-doping, which is commonly applied to electron beam lithography. (See Non-Patent Documents 1 and 2.)
In addition, among known species of water-soluble self-doping polythiophene for antistatic use are poly(3-thiophene-β-butanesulfonate) and poly(3-thiophene-β-ethanesulfonate), (See Non-Patent Documents 1 and 3.)
However, nothing has been reported about the sulfoxyalkylthiophene disclosed in the present invention.
Incidentally, among known species of hydroxyalkynylthiophene is 3-[4-(3-hydroxy-prop-1-ynyl)-thiophen-3-yl]-prop-2-yn-1-ol (3,4HTPO), which is represented by formula [7] below. (See Patent Document 1.)

Patent Document 1: WO Publication No. WO01/19809 (pages, 21, 27, and 41 to 42)
Non-Patent Document 1: “Synth. Met.” Elsevier Sequoia (Netherlands), 1989, vol. 30, p. 305 to 319
Non-Patent Document 2: “Handbook of Conducting Polymers” 2nd ed. Revised and enlarged, Marcel Dekkers Inc. (USA), 1998, p. 930
Non-Patent Document 3: “J. Amer. Chem. Soc.” American Chemical Society (USA), 1987, vol. 109, p. 1858 to 1859